Electrical pull-cord socket



May 6, 1952 o. HOLZAPFEL 2,595,851

ELECTRICAL PULL-CORD SOCKET o. HOLZAPFEI. 2,595,851

ELECTRICAL PULL-CORD SOCKET May 6, 1952 2 SHEETS-SHEET 2 Filed June l, 1951 w f I" 03 71 v7606 f 3 627)' 2g jfrzvezam/t/ Patentedl May 6, 1952 UNITED i STATES PATE-NT OF FICE `Erlli'o'rmcsr. PULL-conn sooner 'otto Holzap'fei, chicago, 111.

:Application June l, 1951,!S'erial N o. '229,379 11 claims. (cristo-5115) `1 This invention relates generally to improvements'inelectri'cal pull-cord sockets and -is particularly directed tothe provision of a pull-cord `socket having `a novel and unique switch mechanism through `which current passes Vcompletely insulated from the rotating parts thereof and the pull-cord whereby to insure safe operation `and long life.

The vprincipal objects of the invention consist `of the provision of an electrical `pull-cord socket in which short crcuiting-of .the socket because of 4heating up of the cord or entanglement thereof with the 4rotating parts of the -socket substantially will be eliminated; in which the occurrence of fires or shock to persons handling same will be materially reduced; which may be installed or replaced easily and `simply without requiring great skill or training; which is inexpensive to manufacture, fool-proof against short circuiting andeliminates the use of open wires therein.

Still another important object of the invention is to provide a pull-cord socket of the character` described having a novel switch mechanism in which -the rotatable parts `of the same are enclosed .and totally insulated .from the electrical parts of Ythe switch.

Still a yfurther object of the invention is to provide a socket of the character described having a novel mechanism for actuating a switch operating pin.

With .theforegoing and votherobjects in view which will .appear as the 4description proceeds, the invention consists of certain novel features of construction,arrangement and a combination of .parts 4hereinafter fully described, illustrated in the accompanying drawings, `and particularly pointed `outin .the .appended claimsVit being understood that various changes .in the form, proportion, size and minor details of the structure maybe made without departingfrom the vspirit or sacrificing any of the advantages of the invention.

For the purpose of facilitating an understand- .ing lof .this invention. there is .illustrated .in the accompanying drawings .a preferred embodiment thereof, ,from an inspection of which, when considered in connection with the following description, -this invention, 'its mode of construction, as-

sembly and operation, and many of its Aadvantages should be readily understood and appreciated.

Referring to the drawings in which the same characters hof reference are employed to indicate corresponding or similar parts throughout the several gures of the drawings:

Fig. 1 is a side elevational view of an electrical pull-cordsocket of the type with which theinvention is concerned.

Fig. 2 isa vertical sectional view taken through an electrical pull-cord socket having .the invention `embodied therein.

Fig. 3 is a sectional view taken through the socket along the line 3 3 of `Fig.. 2 and in the direction indicated.

Fig. 4 .isa sectional view taken along `the `line 4--4 of Fig. 3 and in the direction indicated.

Fig..5 is a perspective view of thecontact arm used inthe socket embodying theinvention.

Fig. `6 is a sectional View -through :the socket taken along the lines 6--5 of Fig. 2 land inthe direction indicated.

Fig. 7 is an .elevational View Ataken along vthe line .of Fig. 3 and in .the general direction indicated, ,portions .being broken away to `show details.

Fig. 8 .is asectional view taken along the'flinc 8-3 of Fig. 'Stand in the direction indicated.

lFig. 9 is a vertical sectional view taken through a portion of thesocket and showing certain details of construction illustrated in Fig. -3 on Aan enlarged scale.

Fig. 10 is a perspective View Iof the ratchet wheel used in the socket embodying .the invention.

Generally, fin devices of the character herewith concerned, current drawn l'from apower line is lpassed through the socket to energize ane'lectric lamp or other device screwed into .or -connected to `one end thereof. In order to permit `alternate ignition and shutting oi of the lamp. a-switch mechanism is interposed in the circuit between one side of the power line and theelec'tric lamp, the switch 'being operated by means of -a pull-cord secured to -the `switch and having a portion thereof disposed on the outside .of the socket. It has been found in .prior art sockets that after prolonged 4use of the lamp, the soc'ket heats up, thereby causing the .pull-cord also to lieatnp. In other instances, the pull-cord .may become entangled in rotating vparts of 4the switch whereby 'to cause a short circuit. Fires and shocks to persons handling 'the socket have occurred repeatedly land a skilled technician is irequired to be summoned in order to replace .or install prior art sockets of the character -herewith concerned. All of these disadvantages substantially are eliminated by means of the 'hereindescribed invention. g

Referring now to the drawings, 'the reference character 20 designates .generally an velectrical pull-cord socket of the type herein concerned.

Same includes a hollow casing cylindrical in formation, which is adapted to contain the operating parts of the socket and is formed from a cap member 22 and an outer casing 23 having cooperating screw threads 24 adapted to be matingly engaged. A power line 25 is received in an opening 26 provided in the crown of the cap 22 and an electric lamp 21 is removably secured in the lower end 28 of the member 22. A pull-cord 29 extends from said casing for operating said lamp.

The cap member is provided with contacts to which the leads of the power line are secured. Referring to Fig. 2, there is disposed in the cap an insulating plug 30 having vertical elongate recesses 3| and 3| arranged diametrically one with the other. The above referred to contacts comprise metal plates 32 and 32 arranged over the openings on the upper surface of the plug 36 as viewed in Fig. 3, and each plate has an offset perforation for receiving therein binding post screws in a manner well-known in the art. The bared ends 33 and 33 of the leads 34 and 34 of the power line are held in engagement with the respective contacts 32 and 32 by means of binding post screws 35 which pass through the perforations (not shown) and are threaded intothe plug 36 thereby holding the contacts 32 and 32 and the bared ends 33 and 33 firmly against the plug surface. It is not believed necessary to enter into great detail concerning this arrangement since it is well-known, and there are many additional ways of securing the contacts physically to the plug 38 and electrically to the leads.

The lower end 28 of the outer housing 23 is of reduced diameter and provides a socket into which the lamp 21 is received. A threaded sheet metal shell 38 is secured on the inside of the portion 28. The shell has the usual convolutions on the interior thereof to form threads 39 for reception of the lamp base. The shell has integrally formed flanges or ears 40 and 4|, diametrically disposed on the upper end thereof as viewed in Fig. 2 for fastening the shell to the bottom end of the inner housing as will be explained.

Disposed within the outer casing 23 is a housing 42 in which the operating parts of the socket 20 are contained. Said housing 42 may be made from phenolic resin or some other non-conducting material and includes a pair of spaced vertical walls 43 and 44, a top wall 45 and a bottom wall 46, said walls being suitably joined to form therebetween a central cavity 41. The bottom wall 41 is'disposed adjacent the ears 40 and 4|, while the top wall is adapted to engage the plug 38. The switch mechanism designated generally 48 is contained in the cavity 41 with means being provided for completing the circuit between the leads 34, 34 and the shell 38.

Referring to Fig. 3, there is shown the construction for completing the circuit between the switch 48 and the leads 34, 34. In the top wall 45 is provided a pair of spaced recesses 49 and 43', each having an enlarged bore 50 and a narrower bore said bores 5I each communicating with the upper surface 52 of Wall 45. A metallic contact prong 53 is disposed in the recess 49 and similar prong 53' is arranged in recess 49. Each of said prongs has a flange 54 on one end thereof while the opposite ends thereof are arranged to enter the recesses 3| and 3 respectively to engage with contacts 32 and 32. In order to maintain engagement of the prongs against the contacts, there is provided a pair of coil springs 56 and 56', one spring 56 being contained in the bore 56 of recess 49 between the lug 54 and wall 45 and the other spring 56' being contained in bore 56 of recess 49' in the same position. Thus, the springs 56, 56' serve to urge the respective prongs 53, 53 upward into engagement with its respective contact 32, 32.

It is noted that the left hand prong 53 is of larger diameter than the prong 53 and likewise the left hand recess 3| is of a larger diameter to accommodate this larger prong. In this manner, the rounded wire 33 will be positively connected with the shell 38 while the hot"`wire 33 will be the one opened when the switch 48 is operated. This will thereby provide an additional safety factor in my device.

Secured to the exterior of wall 44 is an L-shaped conductor strip 58, one arm 59 being secured to the wall 44 by a screw 66, while the other arm 6| is inserted through wall 44, into recess 49 and beneath the end of spring 56. Thus, the lead 34 is electrically connected through contact 32 to prong 53 and spring 56 to the strip 58. On arm 59 is secured a contact button 62 extending outwardly therefrom. To complete the circuit from the strip 58 to the ear 4|, I provide a ilat, resilient metallic strip 63 secured also to the outer surface of wall 44. Said strip 63 has a contact button 64 secured to the surface 65 at the upper end of said strip adapted to contact the button 62. The lower end of the strip 63 is bent as at 68 to extend across the bottom of wall 46, and thence partially into the shell 38. The strip 63 is secured to thewall 44 immediately above said bend 68 by means of a flat plate 10 mounted thereover and screws 1| threaded into the wall 44. The plate 19 is slotted at 66 to permit its being adjusted to change the tension in the member 63.

Mounted on the wall 43 is a C-shaped metallic strip 13 having an upper arm 14 and a lower arm 15 connected by a straight portion 16. The arm 14 is disposed beneath the spring 56 in contact therewith, while the arm 15 is arranged above the ear 48 in contact therewith. Thus, the circuit from lead 34 to the ear 49 is through contact 32, prong 53, spring 56 and metallic strip 13. Screws 61 secure ears 48 and 4| to the bottom Wall 46, and one passes through arm 15. When the lamp is screwed into the socket, the end 61 0f the strip 63 will remain biased into contact with one terminal of the lamp thereby completing the circuit from ear 4| to said end through shell 38 and the lamp.

We will now consider the construction of the switch mechanism 48. Same comprises a shaft 16 journalled for rotation in walls 43 and 44 and having a headed end 11 disposed in recess 18 of the wall 43. Mounted on shaft 16 is a sleeve member 19 having an enlarged diameter portion 88 and a narrower portion 8|, said sleeve member 19 having its ends engaged against the inside of walls 43 and 44 respectively. A ratchet device is mounted on said shaft Which includes a collar 82 mounted on the portion 98, said collar being made from plastic or other insulating material, said collar has a channel 83 along the periphery thereof defined by the spaced upstanding walls 84 and 85. 85 extends into the channel 83. The end 81 of a coil spring 88 is secured to said pin 86, while the second end 89 of said spring is secured to one of the screws 1| as shown in Fig. 2. The end 90 of the pull-cord 29 also is attached to said pin 86, said cord extending through an opening 9| in the housing 23 to a point exteriorthereof. Thus, by

A pin 86 secured between walls 84 and pulling the cord 29'to the right asviewed in Fig. 2, `the collar 82 will be -caused to rotate Vina clockwise direction, expanding Athe spring '88. Upon release ofthe cord29, the spring in returning to its normal direction will rotate the collar in a counter-clockwise direction. Obviously-the cord 29 may be a metal bead-chain or the like as commonto such device.

Mounted on the narrow portion 8| of the sleeve member is a ratchet wheel 92 best shown in Fig. `10. The ratchet 92 preferably is made from plastic or other suitable non-cond-ucting material.

The side 93 of said ratchet has formed thereon a series of steps or teeth 94 each consisting of a at portion 95 tapered inwardly and'terminating in a shoulder portion 96 perpendicular to the vertical axis of the ratchet. The side 91 is formed with `a series of steps or cam formations 99 terminating in shoulder portions 99 perpendicular to the vertical axis of said ratchet. The cam formations are formed so that alternate ones have deeper indentations than intermediate ones. The number of cam formations are equal to the number of steps 94.

When the ratchet wheel is mounted on the narrow portion -8I the side 93 is disposed adjacent the wheel 82 and the side 91 is disposed adjacent the Wallr44.

. The ratchet `92 is adapted to be rotated simultaneously with rotation of the wheel 02. Accord- -ingly, I provide a pair of detents and |0| secured to the exterior of wall 84 and protruding therefrom to engage against the side 93 of the ratchet. To maintain the wheel 82 and ratchet 92 in proper position relative to each other, there is provided a spring |02 having its ends |03 and |04 engaged respectively against the walls 45 and 46 with the body portion of said spring biased against the wheel 82 as at |05.

Mouted in an opening |06 in wall 44 is a reciprocable push rod |01 made from a non-conducting material such as plastic or the like. Said rod |01 is longer than the width of said wall A4 and has one `end |08 disposed outside of said wall and adapted to engage the metallic strip 63. The

`other end |09 is disposed in the cavity 41 and `against the side 91 of the ratchet 92. The rod |01 serves to break the contact between the contact buttons 62 and 64.

The operation of the socket constituting my invention is as follows. Referring to Fig. 9, with the button 64 in contact with the button 62, the circuit from the leads 34 and 34 to the ears 40 and 4| is closed and the lamp will be ignited. In `this condition, the rod |01 will have its end Y |09 disposed against the side 91 of ratchet wheel 92, and the end |08 will be free of the strip 63. To break the circuit the pull-cord 21 is drawn out- -ward whereby 'the end 90 of said cord will exert Vtions 98 and be moved to therlght as viewed in Fig. 10 against the strip 63. Continued movement of the rod |01 to the right will push the resilient strip 63 to the right to move the button 64 lout of contact with'the button 62 breaking the circuit and shutting off the lamp 21. Continued rotation of the ratchet wheel 92 will cause the rod |01 to drop off a shoulder 99 and the cord 29 is released lso vthat the spring 80 will return the wheel 82 to a position where the detents |00 and 6 0| engage against the next shoulders 96. To ignitethe lamp the `pull-cord is again pulled outwardly to turn the wheel 82 and the ratchet-9i. yBecause the cam formations -98 are alternately deeper and shallower, when the rod 01 is engaged on a shallower formation, theffbuttons 62 and 64 will be outof contact whereas when the rod |01 is engaged against in a deeper formation, the buttons will bein contact one With the other to ignite the lamp. Itwill be appreciated that the cam formation 99 kmay be formed asupward ie'ps ,just as well in order to reciprocate the Vrod Since the .co11ar02 and ratchet wheel 92 Vare madeof non-conducting material, it will .be seen that the cord 21 will not be liable to being heated during operation of the lamp nor will ,the socket short `circuit should the said cord vbecome entangled in the operating parts. Also. by mounting the conductor strips 13, 58 and the resilient strip 03 on the exterior of the housing 42 and removed from `the rotating parts `82 and 92, the likelihood of short circuiting, res andelectrocution is substantially eliminated. Replacement and installation of the socket device is easilyand rapidly accomplished without requiring Igreat technical skill.

The operation of the cap 22 in being attached `to lthe vbody of `the device is believed obvious.

Suiice it to say that the cap is rotatable rela- .tive `to the remainder of the socket vso that the .described for illustrative purposes, the structural details are nevertheless capable of wide variation within the :purview of this invention as defined in the appended claims. l

What is claimed and desired to be secured by Letters Patent of the United States is:

1. An electrical pull-cord connector for establishing electrical circuit between a line and an electrical device, comprising an insulating casing having a xed and a movable contact on the outside thereof, the movable contact being biased into engagement with the fixed contact, each contact being connected to a part of the circuit and said contacts when engaged `adapted to establish said circuit, a ratchet device inthe casing and a pull cord connected with the ratchet device and extending outside of the casing and adapted when pulled to Operate the said ratchet device, said ratchet device including a uni-directional rotatable wheel having ratchet teeth whereby the successive pulls of the cord Will rotate the wheel in step-by-step movements,

each step being a fraction of a revolution, said ing and having one end engaging `the movable .contact outside of the casing and the other end engaging a. cam formation of said wheel, the alternate cam formations being of a dimension to position the reciprocabl-e member to move the movable contact free of the fixed contact, while the intermediate conformations being of a different dimension disposing the reciprocable member in a position permitting the contacts to engage, whereby successive pulls of the cord will make and break said circuit.

2. An electrical pull-cord connector for establishing electrical circuit between a line and an electrical device, comprising an insulating casing having a fixed and a movable contact on the' outside thereof, the movable contact being biased into engagement with the fixed contact, each contact being connected to a part of the circuit and said contacts when engaged adapted to establish said circuit, a ratchet device in the casing and a pull cord connected with the ratchet device and e extending outside of the casing' and adapted whenpulled to operate the said ratchet device, said ratchet device including a uni-directional rotatable wheel having ratchet teeth whereby the successive pulls of the cord will rotate the wheel f in step-by-step movements, each step being a fraction of a revolution, said wheel having cam formations corresponding in number to the number of ratchet teeth, a reciprocable member extending through the casing and having one end engaging the movable contact outside of theV casing and the other end engaging a cam formation of said Wheel, the alternate cam formations being of a dimension to p-osition the reciprocable member to move the movable contact free of the fixed contact, While the intermediate conformations being of a different dimension disposing the reciprocable member in a position permitting the contacts to engage, whereby successive pullsvof the cord will make and break said f,

circuit, said device being made from a non-conducting material whereby current passing through the connector will be insulated from said pull-cord.

3A An electrical pull-cord connector for estab- ,7,

lishing electrical circuit Ibetween a line and an electrical device, comprising an insulating casing having a fixed and a movable contact on the outside thereof, the movable contact being biased into engagement with the fixed contact, each con- 1 tact being connected to a part of the circuit and said contacts when engaged adapted to establish said circuit, a ratchet device in the casing and a pull cord connected with the ratchet device and extending outside of the casing and adapted when pulled to operate the said ratchet device, said ratchet device including a uni-directional rotatable wheel having ratchet teeth whereby the successive pulls of the cord will rotate the wheel in step-by-step movements, each step being a fraction of a revolution, said wheel having cam formations corresponding in number to the number of ratchet teeth, a reciprocable member extending through the casing and having one end engaging the movable contact outside of the casing and the other end engaging a cam formation of said Wheel, the alternate cam formations being of a dimension to position the reciprocable member to move the movable contact free of the fixed contact, while` the intermediate conformations being of a different dimension disposing the reciprocable member in a position permitting the contacts to engage, whereby successive pulls of the cord will make and break said circuit, said device including a spring biased rotatable member dis- A lishing electrical circuit between a line and an electrical device, comprising an insulating casing having a fixed and a movable contact on the outside thereof, the movable contact being biased into engagement with the fixed contact, each contact being connected to a part of the circuit and said contacts when engaged adapted to establish said circuit, a ratchet device in the casing and a pull cord connected with the ratchet device and extending outside of the casing and adapted when pulled to operate the said ratchet device, said ratchet device including a uni-directional rotatable wheel having ratchet teeth whereby the successive pulls of the cord will rotate the wheel in step-by-step movements, each step vbeing a fraction of a revolution, said wheel having cam formations corresponding in number to the number of ratchet teeth, a reciprocable member extending through the casing and having one end engaging the movable contact outside of the casing and the other end engaging a cam formation of said wheel, the alternate cam formations being of a dimension to position the reciprocable member to move the movable contact free of the fixed contact, while the intermediate conformations being of a different dimension disposing the reciprocable member in a position permitting the contacts to engage, whereby successive pulls of the cord will make and break said circuit, said device including a spring biased rotatable member disposed adjacent said wheel and having detents engageable with said teeth, said pull-cord being attached to said member for simultaneously rotating said member and said Wheel, said reciprocable member comprising a push rod formed of non-conducting material.

5. An electrical pull-cord connector for establishing electrical circuit between a line and an electrical device, comprising an insulating casing having a xed and a movable contact on the outside thereof, the movable contact being `biased into engagement with the fixed contact, each contact being connected to a part of the circuit and said contacts when engaged adapted to establish said circuit, a ratchet device in the casing and a pull cord connected with the ratchet device and extending outside of the casing and adapted when pulled to operate the said ratchet device, said ratchet device including a uni-directional rotatable wheel having ratchet teeth whereby the successive pulls of the cord will rotate the wheel in step-by-step movements, each step being a fraction of a revolution, said wheel having cam formations corresponding in number to the number of ratchet teeth, a reciprocable member extending through the casing and having one end engaging the movable contact outside of the casing and the other end engaging a cam formation of said wheel, the alternate cam formations being of a dimension to position the reciprocable member to move the movable contact free of the fixed contact, while the intermediate conformations being of a different dimension disposing the reciprocable member in a position permitting the contacts to engage, whereby successive pulls of the cord will make and break said circuit, and a plate member adjustably mounted over said movable contact whereby to permit the tension of said contact to be varied.

6. An electrical pull-cord connector for completing an electrical circuit between a line and an electrical device, comprising an insulating housing having a xed and movable contact on the outside thereof, the movable contact being biased into engagement with the fixed contact,

each contact being connected to a part of ther circuit and said contacts when engaged adapted to complete said circuit, a ratchet device in the housing including a spring biased detent. member having said pull-cord attached thereto with the pull-cord extending outside of the casing, and a. uni-directional ratchet wheel having ratchet teeth disposed in engagement with said member whereby successive pulls of said cord will rotate the wheelin step-by-step movements, each step being a fraction of a revolution, said wheel vhaving cam formations corresponding in number to the number of teeth, a reciprocable push rodV mounted in a wall of said casing and having one end engaging the movable contact outside of the casing and the other end engaging a cam formation, the alternate cam formationsl being of a dimension to move said rod for freeing the movable contact from the xed contact, while the intermediate cam formations being of a different dimension permitting the rod to be moved away from said movable contact disposing the contacts in engagement with each other, whereby successive pulls of the cord will make and break the circuit.

7. An electrical pull-cord connector for completing an electrical circuit between a line and an electrical. device, comprising an insulating housing having a Xed and movable contact on the outside thereof, the movable contact being biased into engagement with the fixed contact, each contact being connected to a part of the circuit and said contacts when engaged adapted to complete said circuit, a ratchet device in the housing including a spring biased detent member having said pull-cord attached thereto with the pull-cord extending outside of the casing, and a uni-directional ratchet wheel having ratchet teeth disposed in engagement with said member whereby successive pulls of said cord will rotate the wheel in step-by-step movements, each step being a fraction of a revolution, said wheel having cam formations corresponding in number to the number of teeth, a reciprocable push rod mounted in a wall of said casing and having one end engaging the movable contact outside of the casing and the other end engaging a cam formation, the alternate cam formations being of a dimension to move said rod for freeing the movable contact from the fixed contact, while the intermediate cam formations being of a different dimension permitting the rod to be moved away from said movable contact disposing the contacts in engagement with each other, whereby successive pulls of the cord will make and break the circuit, said datent member and wheel being formed from non-conducting material whereby current passing through the connector will be insulated from the cord.

8. An electrical pull-cord connector for completing an electrical circuit between a line and an electrical device, comprising an insulating housing having a fixed and movable contact on the outside thereof, the movable contact being biased into engagement with the fixed contact, each contact being connected to a part of the circuit and said contacts when engaged adapted to complete said circuit a ratchet device in the housing including a spring biased detent member having said pull-cord attached thereto with the pull-cord extending outside of the casing, and a uni-directional ratchet wheel having ratchet teeth disposed in engagement with said member whereby successive pulls of said cord will rotate the wheel in step-by-step movement, each ,step

l()l being a fraction of` a revolution, said wheel having cam formations corresponding in number to the number of teeth, a reciprocable push rod mounted in a wall of said casing and having one end engaging the movable contact outside of the casing'and the other end engaging a cam formation, the alternate cam formations being of a dimension to move said rod for freeing the movable contact-from the fixed contact, While the intermediate cam formations being of a different dimension permitting the rod to be moved away from said movable contact disposing the contacts in engagement with each other, whereby successive. pulls of the cord will make and breakthe circuit, said detent member and wheel being formed from non-conducting material whereby current passing through the connector will be insulated from the cord, said rod being made from l a non-conducting material.

9. In an electrical pull-cord socket of the character described including an insulating housing adapted to contain a switch mechanism for making and breaking an electrical circuit betw en a line and an electrical device, a switch mechanism including a Xed and movable contact mounted on the outside of said housing, the movable contact being biased into engagement with the fixed contact, each contact being connected to a part of the circuit and said movable Contactl being movable relative to said fixed contact for making and breaking the circuit, a rotatable detent member having the pull-cord thereto attached, a unidirectional rotatable wheel having ratchet teeth engageable by said member adapted to rotate the wheel in step-bystep movements with successive pulls of the cord, said wheel having a plurality of cam formations corresponding in number to the number of ratchet teeth, a reciprocable rod mounted in a wall of said casing having one end engaging the movable contact outside the casing and the other end engaging a cam formation, said cam formations being of a dimension whereby alternate formations will cause said rod to be moved against said movable contact for moving said contact out of engagement with the fixed contact while intermediate formations permit movement of the rod in a direction permitting said movable contact to engage the xed contact, whereb57 successive pulls the cord will make and break said circuit.

10. In an electrical pull-cord socket of the character described including an insulating housing adapted to contain a switch mechanism for making and breaking an electrical circuit between a line and an electrical device, a switch mechanism including a fixed and movable contact mounted on the outside of said housing, the movable contact being biased into engagement with the fixed Contact, each contact being connected to a part of the circuit and said movable contact being movable relative to said fixed contact for making and breaking the circuit, a rotatable detent member havinf1r the pullcord thereto attached, a undidirectional rotatable wheel having ratchet teeth engageable by said member adapted to rotate the wheel in stepby-step movements with successive pulls of the cord, said wheel having a plurality of cam forthe other end engaging a cam formation, saidA cam formations being of a dimension whereby alternate formations will cause said rod to be moved against, said movable contact for moving said contact out of engagement with the fixed contact while intermediate formations permit movement of the rod in a direction permitting said movable contact to engage the fixed contact, whereby successive pulls of the cord will make and break said circuit, said detent member, wheel and plug being made from insulating material.

11. In an electrical pull-cord socket of the character described including an insulating housing adapted to contain a switch mechanism for making and breaking an electrical circuit between a line and an electrical device, a switch mechanism including a fixed and movable contact mounted on the outside of said housing, the movable contact being biased into engagement with the xed contact, each contact being connected to a part of the circuit and said Vmovable contact being movable relative to said fixed contact for making and breaking the circuit, a rotatable detent member having the pull-cord thereto attached, a unidirectional rotatable wheel having ratchet teeth engageable by said member adapted to rotate the wheel in step-bystep movements with successive pulls of the cord, said wheel having a plurality of cam formations corresponding in number to the num- 12 ber of ratchet teeth, a reciprooable rod mounted in a wall of said casing having one end engaging the movable contact outside the casing and the other end engaging a cam formation, said cam formations being of a dimension whereby alternate formations will cause said rod to be moved against said movable contact for moving said contact out of engagement with the xed contact while intermediate formations permit movement of the rod in a direction permitting said movable contact to engage the fixed contact, whereby successive pulls of the cord will make and break said circuit, said detent member, wheel and plug being made from insulating material, and an adjustable plate member mounted over said movable contact for varying the tension thereof.

OTTO HOLZAPFEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 995,244 Freeman June 13, 1911 2,349,655 Grout May 23, 1944 2,469,120 Kropp May 3, 1949 

